Homeopathy is a form of alternative medicine in which practitioners treat patients
using highly diluted preparations that are believed to cause healthy people to exhibit
symptoms that are similar to those exhibited by the patient. The collective weight
of scientific evidence has found homeopathy to be no more effective than a placebo.

In the context of homeopathy, the term remedy is used to refer to a substance which
has been prepared with a particular procedure and intended for patient use; it is
not to be confused with the generally accepted use of the word, which means "a medicine
or therapy that cures disease or relieves pain".

The basic principle of homeopathy, known as the "law of similars", is "let like
be cured by like." It was first stated by German physician Samuel Hahnemann in 1796.
His "law of similars" is taken on his word as an unproven assertion, and is not
a true law of nature based on the scientific method. Homeopathic remedies are prepared
by serial dilution with shaking by forceful striking on an elastic body, which homeopaths
term succussion. Each dilution followed by succussion is assumed to increase the
effectiveness. Homeopaths call this process potentization. Dilution often continues
until none of the original substance remains. Apart from the symptoms, homeopaths
examine aspects of the patient's physical and psychological state, then homeopathic
reference books known as repertories are consulted, and a remedy is selected based
on the totality of symptoms.

While some individual studies have positive results, systematic reviews of published
trials fail to demonstrate efficacy. Furthermore, higher quality trials tend to
report results that are less positive, and most positive studies have not been replicated
or show methodological problems that prevent them from being considered unambiguous
evidence of homeopathy's efficacy.

Depending on the dilution, homeopathic remedies may not contain any pharmacologically
active molecules, and for such remedies to have pharmacological effect would violate
fundamental principles of science. Modern homeopaths have proposed that water has
a memory that allows homeopathic preparations to work without any of the original
substance; however, there are no verified observations nor scientifically plausible
physical mechanisms for such a phenomenon. The lack of convincing scientific evidence
to support homeopathy's efficacy and its use of remedies lacking active ingredients
have caused homeopathy to be described as pseudoscience, quackery, and a "cruel
deception".

Oral homeopathic remedies are safe at high dilutions recommended by Hahnemann, since
they likely contain no molecules of the original substance, but they may not be
safe at lower dilutions. If injected, homeopathic remedies may carry a risk of infection
if they have not been prepared in a wholly sterile clinical environment. Homeopathy
has been criticized for putting patients at risk due to advice against conventional
medicine such as vaccinations, anti-malarial drugs,and antibiotics.

The regulation and prevalence of homeopathy is highly variable from country to country.
There are no specific legal regulations concerning its use in some countries, while
in others, licenses or degrees in conventional medicine from accredited universities
are required. In several countries, homeopathy is covered by the national insurance
to different extents, while in some it is fully integrated into the national healthcare
system. In many countries, the laws that govern the regulation and testing of conventional
drugs do not apply to homeopathic remedies.

Philosophy

Homeopathy is a vitalist philosophy that interprets diseases and sickness as caused
by disturbances in a hypothetical vital force or life force. It sees these disturbances
as manifesting themselves as unique symptoms. Homeopathy maintains that the vital
force has the ability to react and adapt to internal and external causes, which
homeopaths refer to as the law of susceptibility. The law of susceptibility implies
that a negative state of mind can attract hypothetical disease entities called miasms
to invade the body and produce symptoms of diseases.However, Hahnemann rejected
the notion of a disease as a separate thing or invading entity and insisted that
it was always part of the "living whole".[36] Hahnemann proposed homeopathy in reaction
to the state of traditional western medicine at that time, which often was brutal
and more harmful than helpful. Hahnemann coined the expression "allopathic medicine,"
which was used to pejoratively refer to traditional western medicine.

Law of similars

Hahnemann observed from his experiments with cinchona bark, used as a treatment
for malaria, that the effects he experienced from ingesting the bark were similar
to the symptoms of malaria. He therefore decided that cure proceeds through similarity,
and that treatments must be able to produce symptoms in healthy individuals similar
to those of the disease being treated.[38] Through further experiments with other
substances, Hahnemann conceived of the law of similars, otherwise known as "let
like be cured by like" (Latin: similia similibus curentur) as a fundamental healing
principle. He believed that by using drugs to induce symptoms, the artificial symptoms
would stimulate the vital force, causing it to neutralise and expel the original
disease and that this artificial disturbance would naturally subside when the dosing
ceased.[38] It is based on the belief that a substance that in large doses will
produce symptoms of a specific disease will, in extremely small doses, cure it.

Hahnemann's law of similars is an ipse dixit axiom, in other words an unproven assertion
made by Hahnemann, and not a true law of nature.

Miasms and disease

In 1828, Hahnemann introduced the concept of miasms; underlying causes for many
known diseases. A miasm is often defined by homeopaths as an imputed "peculiar morbid
derangement of [the] vital force".[42] Hahnemann associated each miasm with specific
diseases, with each miasm seen as the root cause of several diseases. According
to Hahnemann, initial exposure to miasms causes local symptoms, such as skin or
venereal diseases, but if these symptoms are suppressed by medication, the cause
goes deeper and begins to manifest itself as diseases of the internal organs. Homeopathy
maintains that treating diseases by directly opposing their symptoms, as is sometimes
done in conventional medicine, is ineffective because all "disease can generally
be traced to some latent, deep-seated, underlying chronic, or inherited tendency".[44]
The underlying imputed miasm still remains, and deep-seated ailments can be corrected
only by removing the deeper disturbance of the vital force.

Hahnemann originally presented only three miasms, of which the most important was
"psora" (Greek for itch), described as being related to any itching diseases of
the skin, supposed to be derived from suppressed scabies, and claimed to be the
foundation of many further disease conditions. Hahnemann believed psora to be the
cause of such diseases as epilepsy, cancer, jaundice, deafness, and cataracts.[41]
Since Hahnemann's time, other miasms have been proposed, some replacing one or more
of psora's proposed functions, including tubercular miasms and cancer miasms.

Hahnemann's miasm theory remains disputed and controversial within homeopathy even
in modern times. In 1978, Anthony Campbell, then a consultant physician at The Royal
London Homeopathic Hospital, criticised statements by George Vithoulkas claiming
that syphilis, when treated with antibiotics, would develop into secondary and tertiary
syphilis with involvement of the central nervous system. This conflicts with scientific
studies, which indicate that penicillin treatment produces a complete cure of syphilis
in more than 90% of cases.[46] Campbell described this as "a thoroughly irresponsible
statement that could mislead an unfortunate layman into refusing orthodox treatment".

The theory of miasms has been criticized as an explanation developed by Hahnemann
to preserve the system of homeopathy in the face of treatment failures, and for
being inadequate to cover the many hundreds of sorts of diseases, as well as for
failing to explain disease predispositions as well as genetics, environmental factors
and the unique disease history of each patient.

Remedies

Remedy is a technical term in homeopathy that refers to a substance which has been
prepared with a particular procedure and intended for patient use; it is not to
be confused with the generally accepted use of the word, which means "a medicine
or therapy that cures disease or relieves pain". Homeopathic practitioners rely
on two types of reference when prescribing remedies: Materia medica and repertories.
A homeopathic Materia medica is a collection of "drug pictures", organised alphabetically
by “remedy,” that describes the symptom patterns associated with individual remedies.
A homeopathic repertory is an index of disease symptoms that lists remedies associated
with specific symptoms.

Homeopathy uses many animal, plant, mineral, and synthetic substances in its remedies.
Examples include Arsenicum album (arsenic oxide), Natrum muriaticum (sodium chloride
or table salt), Lachesis muta (the venom of the bushmaster snake), Opium, and Thyroidinum
(thyroid hormone). Homeopaths also use treatments called nosodes (from the Greek
nosos, disease) made from diseased or pathological products such as fecal, urinary,
and respiratory discharges, blood, and tissue.Homeopathic remedies prepared from
healthy specimens are called sarcodes.

Some modern homeopaths have considered more esoteric bases for remedies, known as
imponderables because they do not originate from a material but from electromagnetic
energy presumed to have been "captured" by alcohol or lactose. Examples include
X-rays and sunlight. Today there are about 3,000 different remedies commonly used
in homeopathy.[citation needed] Some homeopaths also use techniques that are regarded
by other practitioners as controversial. These include paper remedies, where the
substance and dilution are written on a piece of paper and either pinned to the
patient's clothing, put in their pocket, or placed under a glass of water that is
then given to the patient, as well as the use of radionics to prepare remedies.
Such practices have been strongly criticised by classical homeopaths as unfounded,
speculative, and verging upon magic and superstition.

Preparation

In producing remedies for diseases, homeopaths use a process called dynamisation
or potentisation whereby a substance is diluted with alcohol or distilled water
and then vigorously shaken by ten hard strikes against an elastic body in a process
called succussion. Hahnemann advocated using substances that produce symptoms like
those of the disease being treated, but found that material doses intensified the
symptoms and exacerbated the condition, sometimes causing dangerous toxic reactions.
He therefore specified that the substances be diluted. Hahnemann believed that the
succussion activated the vital energy of the diluted substance[56] and made it stronger.
To facilitate succussion, Hahnemann had a saddle-maker construct a special wooden
striking board covered in leather on one side and stuffed with horsehair.[57][58]
Insoluble solids, such as quartz and oyster shell, are diluted by grinding them
with lactose (trituration).

Dilutions

Three logarithmic potency scales are in regular use in homeopathy. Hahnemann created
the centesimal or C scale, diluting a substance by a factor of 100 at each stage.
The centesimal scale was favored by Hahnemann for most of his life. A 2C dilution
requires a substance to be diluted to one part in one hundred, and then some of
that diluted solution diluted by a further factor of one hundred. This works out
to one part of the original substance in 10,000 parts of the solution. A 6C dilution
repeats this process six times, ending up with the original material diluted by
a factor of 100−6=10−12 (one part in one trillion or 1/1,000,000,000,000). Higher
dilutions follow the same pattern. In homeopathy, a solution that is more dilute
is described as having a higher potency, and more dilute substances are considered
by homeopaths to be stronger and deeper-acting remedies.The end product is often
so diluted that it is indistinguishable from the dilutant (pure water, sugar or
alcohol).

Hahnemann advocated 30C dilutions for most purposes (that is, dilution by a factor
of 1060).In Hahnemann's time it was reasonable to assume that remedies could be
diluted indefinitely, as the concept of the atom or molecule as the smallest possible
unit of a chemical substance was just beginning to be recognized. The greatest dilution
that is reasonably likely to contain even one molecule of the original substance
is 12C. Some homeopaths developed a decimal scale (D or X), diluting the substance
to ten times its original volume each stage. The D or X scale dilution is therefore
half that of the same value of the C scale; for example, "12X" is the same level
of dilution as "6C". Hahnemann never used this scale but it was very popular throughout
the 19th century and still is in Europe. This potency scale appears to have been
introduced in the 1830s by the American homeopath, Constantine Hering. In the last
ten years of his life, Hahnemann also developed a quintamillesimal (Q) or LM scale
diluting the drug 1 part in 50,000 parts of diluent. A given dilution on the Q scale
is roughly 2.35 times its designation on the C scale. For example a remedy described
as "20Q" has about the same concentration as a "47C" remedy. Critics and advocates
of homeopathy alike commonly attempt to illustrate the dilutions involved in homeopathy
with analogies.[70] Hahnemann is reported to have joked that a suitable procedure
to deal with an epidemic would be to empty a bottle of poison into Lake Geneva,
if it could be succussed 60 times.[71][72] Another example given by a critic of
homeopathy states that a 12C solution is equivalent to a "pinch of salt in both
the North and South Atlantic Oceans", which is approximately correct. One third
of a drop of some original substance diluted into all the water on earth would produce
a remedy with a concentration of about 13C. A popular homeopathic treatment for
the flu is a 200C dilution of duck liver, marketed under the name Oscillococcinum.
As there are only about 1080 atoms in the entire observable universe, a dilution
of one molecule in the observable universe would be about 40C. Oscillococcinum would
thus require 10320 more universes to simply have one molecule in the final substance.The
high dilutions characteristically used are often considered to be the most controversial
and implausible aspect of homeopathy.

Dilution debate

Not all homeopaths advocate extremely high dilutions. Many of the early homeopaths
were originally doctors and generally used lower dilutions such as "3X" or "6X",
rarely going beyond "12X". The split between lower and higher dilutions followed
ideological lines. Those favoring low dilutions stressed pathology and a strong
link to conventional medicine, while those favoring high dilutions emphasised vital
force, miasms and a spiritual interpretation of disease. Some products with such
relatively lower dilutions continue to be sold, but like their counterparts, they
have not been conclusively demonstrated to have any effect beyond that of a placebo.

Provings

Hahnemann experimented on himself and others for several years before using remedies
on patients. His experiments did not initially consist of giving remedies to the
sick, because he thought that the most similar remedy, by virtue of its ability
to induce symptoms similar to the disease itself, would make it impossible to determine
which symptoms came from the remedy and which from the disease itself. Therefore,
sick people were excluded from these experiments. The method used for determining
which remedies were suitable for specific diseases was called proving, after the
original German word Prüfung, meaning "test". A homeopathic proving is the method
by which the profile of a homeopathic remedy is determined.

At first Hahnemann used material doses for provings, but he later advocated proving
with remedies at a 30C dilution,[63] and most modern provings are carried out using
ultradilute remedies in which it is highly unlikely that any of the original molecules
remain.[83] During the proving process, Hahnemann administered remedies to healthy
volunteers, and the resulting symptoms were compiled by observers into a drug picture.
The volunteers were observed for months at a time and made to keep extensive journals
detailing all of their symptoms at specific times throughout the day. They were
forbidden from consuming coffee, tea, spices, or wine for the duration of the experiment;
playing chess was also prohibited because Hahnemann considered it to be "too exciting",
though they were allowed to drink beer and encouraged to exercise in moderation.
After the experiments were over, Hahnemann made the volunteers take an oath swearing
that what they reported in their journals was the truth, at which time he would
interrogate them extensively concerning their symptoms.

Provings have been described as important in the development of the clinical trial,
due to their early use of simple control groups, systematic and quantitative procedures,
and some of the first application of statistics in medicine.[84] The lengthy records
of self-experimentation by homeopaths have occasionally proven useful in the development
of modern drugs: For example, evidence that nitroglycerin might be useful as a treatment
for angina was discovered by looking through homeopathic provings, though homeopaths
themselves never used it for that purpose at that time.The first recorded provings
were published by Hahnemann in his 1796 Essay on a New Principle. His Fragmenta
de Viribus (1805)contained the results of 27 provings, and his 1810 Materia Medica
Pura contained 65.[88] For James Tyler Kent's 1905 Lectures on Homoeopathic Materia
Medica, 217 remedies underwent provings and newer substances are continually added
to contemporary versions.

Physical, mental, and emotional state examination; Repertories

Homeopaths generally begin with detailed examinations of their patients' histories,
including questions regarding their physical, mental and emotional states, their
life circumstances and any physical or emotional illnesses. The homeopath then attempts
to translate this information into a complex formula of mental and physical symptoms,
including likes, dislikes, innate predispositions and even body type.[89] From these
symptoms, the homeopath chooses how to treat the patient. A compilation of reports
of many homeopathic provings, supplemented with clinical data, is known as a homeopathic
materia medica. But because a practitioner first needs to explore the remedies for
a particular symptom rather than looking up the symptoms for a particular remedy,
the homeopathic repertory, which is an index of symptoms, lists after each symptom
those remedies that are associated with it. Repertories are often very extensive
and may include data extracted from multiple sources of materia medica. There is
often lively debate among compilers of repertories and practitioners over the veracity
of a particular inclusion.

The first symptomatic index of the homeopathic materia medica was arranged by Hahnemann.
Soon after, one of his students Clemens von Bönninghausen, created the Therapeutic
Pocket Book, another homeopathic repertory.[90] The first such homeopathic repertory
was Georg Jahr's Symptomenkodex, published in German (1835), which was then first
translated to English (1838) by Constantine Hering as the Repertory to the more
Characteristic Symptoms of Materia Medica. This version was less focused on disease
categories and would be the forerunner to Kent's later works.It consisted of three
large volumes. Such repertories increased in size and detail as time progressed.

Some diversity in approaches to treatments exists among homeopaths. Classical homeopathy
generally involves detailed examinations of a patient's history and infrequent doses
of a single remedy as the patient is monitored for improvements in symptoms, while
clinical homeopathy involves combinations of remedies to address the various symptoms
of an illness.

Homeopathic pills

Homeopathic pills are made from an inert substance (often sugars, typically lactose),
upon which a drop of liquid homeopathic preparation is placed.

Active ingredients

The list of ingredients seen on remedies may confuse consumers into believing that
the product actually contains those ingredients. According to normal homeopathic
practice, remedies are prepared starting with active ingredients that are often
serially diluted to the point where the finished product no longer contains any
biologically "active ingredients" as that term is normally defined. The list of
ingredients normally refers to the ingredients originally used in their preparation.
Following is a demonstrative example:

Zicam Cold Remedy is marketed as an "unapproved homeopathic" product.It contains
a number of highly diluted ingredients that are listed as "inactive ingredients"
on the label. Some of the homeopathic ingredients used in the preparation of Zicam
are galphimia glauca,[95] histamine dihydrochloride (homeopathic name, histaminum
hydrochloricum),[96] luffa operculata,[97] and sulfur. Although the product is marked
"homeopathic", it does contain two ingredients that are only slightly diluted, zinc
acetate (2X = 1/100 dilution) and zinc gluconate (1X = 1/10 dilution),[94] which
means that both are present in a concentration that contains biologically active
ingredients. In fact, they are strong enough to have caused some people to lose
their sense of smell, a condition termed anosmia. This illustrates why taking a
product marked "homeopathic", especially an overdose,[99] can still be dangerous
because it may contain biologically active ingredients.

Scientific skeptics highlight the lack of active ingredients in homeopathic products
by taking large overdoses - examples include James Randi and the 10:23 campaign
groups.[99] None of the hundreds of demonstrators in the UK, Australia, New Zealand,
Canada and the US were injured and "no one was cured of anything, either".[100]
Some marketers of remedies state that one "cannot overdose on homeopathic medicines".

Related practices

Isopathy

Isopathy is a therapy derived from homeopathy and was invented by Johann Joseph
Wilhelm Lux in the 1830s. Isopathy differs from homeopathy in general in that the
remedies, known as "nosodes", are made up either from things that cause the disease
or from products of the disease, such as pus.[50][102] Many so-called "homeopathic
vaccines" are a form of isopathy.

Flower remedies

Flower remedies can be produced by placing flowers in water and exposing them to
sunlight. The most famous of these are the Bach flower remedies, which were developed
by the physician and homeopath Edward Bach. Although the proponents of these remedies
share homeopathy's vitalist world-view and the remedies are claimed to act through
the same hypothetical "vital force" as homeopathy, the method of preparation is
different. Bach flower remedies are prepared in "gentler" ways such as placing flowers
in bowls of sunlit water, and the remedies are not succussed. There is no convincing
scientific or clinical evidence for flower remedies being effective.

Veterinary use

The idea of using homeopathy as a treatment for other animals, termed veterinary
homeopathy, dates back to the inception of homeopathy; Hahnemann himself wrote and
spoke of the use of homeopathy in animals other than humans.[106] The FDA has not
approved homeopathic products as veterinary medicine in the U.S. In the UK, veterinary
surgeons who use homeopathy belong to the Faculty of Homeopathy and/or to the British
Association of Homeopathic Veterinary Surgeons. Animals may be treated only by qualified
veterinary surgeons in the UK and some other countries. Internationally, the body
that supports and represents homeopathic veterinarians is the International Association
for Veterinary Homeopathy. The use of homeopathy in veterinary medicine is controversial,
as there has been little scientific investigation and current research in the field
is not of a high enough standard to provide reliable data. Other studies have also
found that giving animals placebos can play active roles in influencing pet owners
to believe in the effectiveness of the treatment when none exists.

Electrohomeopathy

Electrohomeopathy was a 19th century practice combining homeopathy with electric
treatment.

Evidence

Homeopathy's efficacy is unsupported by the collective weight of modern scientific
research. The extreme dilutions used in homeopathic preparations usually leave none
of the original material in the final product. The modern mechanism proposed by
homeopaths, water memory, is considered implausible in that short-range order in
water only persists for about 1 picosecond. Pharmacological effect without active
ingredients is inconsistent with the observed dose-response relationships of conventional
drugs, leaving only non-specific placebo effects or various novel explanations.
The proposed rationale for these extreme dilutions – that the water contains the
"memory" or "vibration" from the diluted ingredient – is counter to the laws of
chemistry and physics, such as the law of mass action.[108] The lack of convincing
scientific evidence supporting its efficacy[23] and its use of remedies without
active ingredients have led to characterizations as pseudoscience and quackery,
or, in the words of a 1998 medical review, "placebo therapy at best and quackery
at worst." Use of homeopathy may delay or replace effective medical treatment, worsening
outcomes or exposing the patients to increased risk.

Referring specifically to homeopathy, the British House of Commons Science and Technology
Committee has stated:

In the Committee’s view, homeopathy is a placebo treatment and the Government should
have a policy on prescribing placebos. The Government is reluctant to address the
appropriateness and ethics of prescribing placebos to patients, which usually relies
on some degree of patient deception. Prescribing of placebos is not consistent with
informed patient choice - which the Government claims is very important - as it
means patients do not have all the information needed to make choice meaningful.

Beyond ethical issues and the integrity of the doctor-patient relationship, prescribing
pure placebos is bad medicine. Their effect is unreliable and unpredictable and
cannot form the sole basis of any treatment on the NHS.

The National Center for Complementary and Alternative Medicine of the United States'
National Institutes of Health states:

Homeopathy is a controversial area of CAM because a number of its key concepts are
not consistent with established laws of science (particularly chemistry and physics).
Critics think it is implausible that a remedy containing a miniscule amount of an
active ingredient (sometimes not a single molecule of the original compound) can
have any biological effect—beneficial or otherwise. For these reasons, critics argue
that continuing the scientific study of homeopathy is not worthwhile. Others point
to observational and anecdotal evidence that homeopathy does work and argue that
it should not be rejected just because science has not been able to explain it.

High dilutions

The extremely high dilutions in homeopathy have been a main point of criticism.
Homeopathic remedies are usually diluted to the point where there are no molecules
from the original solution left in a dose of the final remedy.[109] Homeopaths contend
that the methodical dilution of a substance, beginning with a 10% or lower solution
and working downwards, with shaking after each dilution, produces a therapeutically
active remedy, in contrast to therapeutically inert water. Since even the longest-lived
noncovalent structures in liquid water at room temperature are stable for only a
few picoseconds, critics have concluded that any effect that might have been present
from the original substance can no longer exist.[117] No evidence of stable clusters
of water molecules was found when homeopathic remedies were studied using NMR.

Furthermore, since water will have been in contact with millions of different substances
throughout its history, critics point out that water is therefore an extreme dilution
of almost any conceivable substance. By drinking water one would, according to this
interpretation, receive treatment for every imaginable condition.

Practitioners of homeopathy contend that higher dilutions produce stronger medicinal
effects. This idea is inconsistent with the observed dose-response relationships
of conventional drugs, where the effects are dependent on the concentration of the
active ingredient in the body. This dose-response relationship has been confirmed
in myriad experiments on organisms as diverse as nematodes, rats, and humans.

Physicist Robert L. Park, former executive director of the American Physical Society,
has noted that:

since the least amount of a substance in a solution is one molecule, a 30C solution
would have to have at least one molecule of the original substance dissolved in
a minimum of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000
molecules of water. This would require a container more than 30,000,000,000 times
the size of the Earth.

Park has also noted that, "to expect to get even one molecule of the 'medicinal'
substance allegedly present in 30X pills, it would be necessary to take some two
billion of them, which would total about a thousand tons of lactose plus whatever
impurities the lactose contained".

The laws of chemistry state that there is a limit to the dilution that can be made
without losing the original substance altogether.[20] This limit, which is related
to Avogadro's number, is roughly equal to homeopathic potencies of 12C or 24X (1
part in 1024).

Scientific tests run by both the BBC's Horizon and ABC's 20/20 programs were unable
to differentiate homeopathic dilutions from water, even when using tests suggested
by homeopaths themselves.

Effectiveness

The effectiveness of homeopathy has been in dispute since its inception. One of
the earliest double blind studies concerning homeopathy was sponsored by the British
government during World War II in which volunteers tested the effectiveness of homeopathic
remedies against diluted mustard gas burns.The methodological quality of the research
base is generally low, with such problems as weaknesses in design or reporting,
small sample size, and selection bias. No individual preparation has been unambiguously
demonstrated to be different from a placebo. Further, as the quality of the trials
become better, the evidence for homeopathy preparations being effective diminishes,
and the highest-quality trials show that the remedies themselves have no effect.Abstract
concepts within theoretical physics have been invoked to suggest explanations of
how or why remedies might work, including quantum entanglement,[128] the theory
of relativity and chaos theory. However, the explanations are offered by nonspecialists
within the field, and often include speculations that are incorrect in their application
of the concepts and not supported by actual experiments. A 2010 inquiry into the
evidence base for homeopathy conducted by the United Kingdom's House of Commons
Science and Technology Committee concluded that homeopathy is no more effective
than placebo.

Meta-analyses

Meta-analyses, in which large groups of studies are analysed and conclusions drawn
based on the results as a whole, have been used to evaluate the effectiveness of
homeopathy. Early meta-analyses investigating homeopathic remedies showed slightly
positive results among the studies examined, but such studies have warned that it
was impossible to draw firm conclusions due to low methodological quality and difficulty
in controlling for publication bias in the studies reviewed. One of the positive
meta-analyses, by Linde, et al., was later qualified by the authors, who wrote:

The evidence of bias [in homeopathic trials] weakens the findings of our original
meta-analysis. Since we completed our literature search in 1995, a considerable
number of new homeopathy trials have been published. The fact that a number of the
new high-quality trials...have negative results, and a recent update of our review
for the most "original" subtype of homeopathy (classical or individualized homeopathy),
seem to confirm the finding that more rigorous trials have less-promising results.
It seems, therefore, likely that our meta-analysis at least overestimated the effects
of homeopathic treatments.

In 2001, a meta-analysis of clinical trials on the effectiveness of homeopathy concluded
that earlier clinical trials showed signs of major weakness in methodology and reporting,
and that homeopathy trials were less randomized and reported less on dropouts than
other types of trials.

In 2002, a review of systematic reviews found that higher-quality trials tended
to have less positive results, to the point that those results were clinically irrelevant.
Also, when taking collectively all the systematic reviews, there was no convincing
evidence that any homeopathic remedy had better effects than placebo, and current
evidence did not allow to recommend its usage in clinical treatment.

In 2005, a systematic review of the representation of homeopathy in the medical
literature suggested that mainstream journals had a publication bias against clinical
trials of homeopathy that showed positive results, and the opposite was the case
for complementary and alternative medicine journals. The authors suggested that
this could be due to an involuntary bias, or otherwise a submission bias, in which
positive trials tend to be sent to CAM journals and negatives ones to mainstream
journals. Reviews in all journals approached the subject in an apparently impartial
manner, though most of the reviews published in CAM journals made no mention of
the plausibility of homeopathy, whereas 9 out of 10 reviews in mainstream journals
mentioned a lack of plausibility of homeopathy in the introduction.

In 2005, The Lancet medical journal published a meta-analysis of 110 placebo-controlled
homeopathy trials and 110 matched medical trials based upon the Swiss government's
Program for Evaluating Complementary Medicine, or PEK. The study concluded that
its findings were compatible with the notion that the clinical effects of homeopathy
are nothing more than placebo effects.

A 2006 meta-analysis of six trials evaluating homeopathic treatments to reduce cancer
therapy side-effects following radiotherapy and chemotherapy found "encouraging
but not convincing" evidence in support of homeopathic treatment. Their analysis
concluded that there was "insufficient evidence to support clinical efficacy of
homeopathic therapy in cancer care".

A 2007 systematic review of homeopathy for children and adolescents found that the
evidence for attention-deficit hyperactivity disorder and childhood diarrhea was
mixed. No difference from placebo was found for adenoid vegetation, asthma, or upper
respiratory tract infection. Evidence was not sufficient to recommend any therapeutic
or preventative intervention.

The Cochrane Library found insufficient clinical evidence to evaluate the efficacy
of homeopathic treatments for asthma dementia, or for the use of homeopathy in induction
of labor. Other researchers found no evidence that homeopathy is beneficial for
osteoarthritis, migraines or delayed-onset muscle soreness.

Health organisations such as the UK's National Health Service, the American Medical
Association, and the FASEB have issued statements of their conclusion that there
is no convincing scientific evidence to support the use of homeopathic treatments
in medicine. Clinical studies of the medical efficacy of homeopathy have been criticised
by some homeopaths as being irrelevant because they do not test "classical homeopathy".
There have, however, been a number of clinical trials that have tested individualized
homeopathy. A 1998 review found 32 trials that met their inclusion criteria, 19
of which were placebo-controlled and provided enough data for meta-analysis. These
19 studies showed a pooled odds ratio of 1.17 to 2.23 in favor of individualized
homeopathy over the placebo, but no difference was seen when the analysis was restricted
to the methodologically best trials. The authors concluded "that the results of
the available randomized trials suggest that individualized homeopathy has an effect
over placebo. The evidence, however, is not convincing because of methodological
shortcomings and inconsistencies." Jay Shelton, author of a book on homeopathy,
has stated that the claim assumes without evidence that classical, individualized
homeopathy works better than nonclassical variations.

Jack Killen, acting deputy director of the National Center for Complementary and
Alternative Medicine, says homeopathy "goes beyond current understanding of chemistry
and physics." He adds: "There is, to my knowledge, no condition for which homeopathy
has been proven to be an effective treatment."

Explanations of effects

Mainstream science offers a variety of explanations for how homeopathy, if the preparations
themselves are ineffective, may appear to cure diseases or alleviate symptoms:

• Unassisted natural healing — time and the body's ability to heal without assistance
can eliminate many diseases of their own accord

• Unrecognized treatments — an unrelated food, exercise, environmental agent or
treatment for a different ailment, may have occurred

• Regression toward the mean — since many diseases or conditions are cyclical, symptoms
vary over time and patients tend to seek care when discomfort is greatest, they
may feel better anyway but because the timing of the visit to the homeopath they
attribute improvement to the remedy taken

• Non-homeopathic treatment — patients may also receive non-homeopathic care simultaneous
with homeopathic treatment, and this is responsible for improvement though a portion
or all of the improvement may be attributed to the remedy

• Cessation of unpleasant treatment — often homeopaths recommend patients stop getting
conventional treatment such as surgery or drugs, which can cause unpleasant side-effects;
improvements are attributed to homeopathy when the actual cause is the cessation
of the treatment causing side-effects in the first place

• Lifestyle changes — homeopaths often recommend diet and exercise, as well as limitations
in alcohol or coffee consumption and stress reduction, all of which can increase
health and decrease symptoms

• The placebo effect — the intensive consultation process and expectations for the
homeopathic preparations can result in the release of endorphins or other body-effecting
chemicals that alleviate pain or other symptoms, or otherwise affect an individual's
biology

• Psychological healing — the care, concern and reassurance provided by a homeopath
as part of the consultation can assure the patient the symptoms are minor and easily
treated, or alleviate tension that could exacerbate a preexisting condition.[citation
needed] This caring engagement can prove particularly effective when conventional
physicians have limited time with the patient or cannot provide a diagnosis or treatment.

• Publishing standards, p-value - Even if something is not effective, the way publishing
works means that you must still expect about 1 in 20 tests to show that it is effective.
The standard to publish a “positive effect” is as follows - If something is assumed
to be false, and then the outcome of the experiment has only about a 1 in 20 chance
of happening, then you can publish that it is effective. This means that about 1
in 20 tests will show homeopathy works, even if it is in fact false.

• Publication bias - If a believer in something conducts a test of homeopathy and
the test says that something is wrong, they might not publish that there will be
no effect, because that would mean they are wrong in their belief. But they would
be expected to publish when there is a positive effect, because this means their
belief is not wrong. So many of the “disproving” tests of that something may not
get published. Even though something is false, since we already expect about 1 in
20 tests to erroneously show it is true, we get even more than about 1 in 20 publications
showing that homeopathy is not false. This is called publication bias.

• A meta-analysis combines the results of several studies.A systematic review is
a literature review focused on a research question that tries to identify, appraise,
select and synthesize all high quality research evidence relevant to that question.

Effects in other biological systems

While some articles have suggested that homeopathic solutions of high dilution can
have statistically significant effects on organic processes including the growth
of grain, histamine release by leukocytes,and enzyme reactions, such evidence is
disputed since attempts to replicate them have failed.

In 1987, French immunologist Jacques Benveniste submitted a paper to the journal
Nature while working at INSERM. The paper purported to have discovered that basophils,
a type of white blood cell, released histamine when exposed to a homeopathic dilution
of anti-immunoglobulin E antibody. The journal editors, sceptical of the results,
requested that the study be replicated in a separate laboratory. Upon replication
in four separate laboratories the study was published. Still sceptical of the findings,
Nature assembled an independent investigative team to determine the accuracy of
the research, consisting of Nature editor and physicist Sir John Maddox, American
scientific fraud investigator and chemist Walter Stewart, and sceptic and magician
James Randi. After investigating the findings and methodology of the experiment,
the team found that the experiments were "statistically ill-controlled", "interpretation
has been clouded by the exclusion of measurements in conflict with the claim", and
concluded, "We believe that experimental data have been uncritically assessed and
their imperfections inadequately reported." James Randi stated that he doubted that
there had been any conscious fraud, but that the researchers had allowed "wishful
thinking" to influence their interpretation of the data.

Methodological and publication issues

Ben Goldacre published an article on homeopathy in The Lancet, stating the research
on homeopathy is problematic for a variety of reasons. These included the high publication
biases of alternative therapy journals, with very few articles reporting null results;
ignoring meta-analytic studies in favour of cherry picked positive results; and
the promotion of an observational study (that Goldacre described as "little more
than a customer-satisfaction survey") as if it were more informative than a series
of randomized trials. Goldacre also states that homeopaths who misrepresent scientific
evidence to a scientifically illiterate public, have "...walled themselves off from
academic medicine, and critique has been all too often met with avoidance rather
than argument."

Ethics and safety

As homeopathic remedies usually contain only water and/or alcohol, they are thought
to be generally safe. Only in rare cases are the original ingredients present at
detectable levels. This may be due to improper preparation or intentional low dilution.
Instances of arsenic poisoning have occurred after use of arsenic-containing homeopathic
preparations. Zicam Cold remedy Nasal Gel, which contains 2X (1:100) zinc gluconate,
reportedly caused a small percentage of users to lose their sense of smell;[166]
340 cases were settled out of court in 2006 for 12 million U.S. dollars. In 2009,
the FDA advised consumers to stop using three discontinued cold remedy products
manufactured by Zicam because it could cause permanent damage to users' sense of
smell.[168] Zicam was launched without a New Drug Application (NDA) under a provision
in the FDA’s Compliance Policy Guide called "Conditions Under Which Homeopathic
Drugs May be Marketed" (CPG 7132.15), but the FDA warned Zicam via a Warning Letter
that this policy does not apply when there is a health risk to consumers.

Critics of homeopathy have cited other concerns over homeopathic medicine, most
seriously cases of patients of homeopathy failing to receive proper treatment for
diseases that could have been easily diagnosed and managed with conventional medicine
and who have died as a result[170] and the "marketing practice" of criticizing and
downplaying the effectiveness of mainstream medicine. Homeopaths claim that use
of conventional medicines will "push the disease deeper" and cause more serious
conditions, a process referred to as "suppression". Some homeopaths (particularly
those who are non-physicians) advise their patients against immunisation. Some homeopaths
suggest that vaccines be replaced with homeopathic "nosodes", created from biological
material such as pus, diseased tissue, bacilli from sputum or (in the case of "bowel
nosodes") feces.[174] While Hahnemann was opposed to such preparations, modern homeopaths
often use them although there is no evidence to indicate they have any beneficial
effects. Cases of homeopaths advising against the use of anti-malarial drugs have
been identified.This puts visitors to the tropics who take this advice in severe
danger, since homeopathic remedies are completely ineffective against the malaria
parasite.Also, in one case in 2004, a homeopath instructed one of her patients to
stop taking conventional medication for a heart condition, advising her on 22 June
2004 to "Stop ALL medications including homeopathic", advising her on or around
20 August that she no longer needed to take her heart medication, and adding on
23 August, "She just cannot take ANY drugs – I have suggested some homeopathic remedies
... I feel confident that if she follows the advice she will regain her health."
The patient was admitted to hospital the next day, and died eight days later, the
final diagnosis being "acute heart failure due to treatment discontinuation".

In 1978, Anthony Campbell, then a consultant physician at The Royal London Homeopathic
Hospital, criticised statements made by George Vithoulkas to promote his homeopathic
treatments. Vithoulkas stated that syphilis, when treated with antibiotics, would
develop into secondary and tertiary syphilis with involvement of the central nervous
system. Campbell described this as a thoroughly irresponsible statement that could
mislead an unfortunate layperson into refusing conventional medical treatment. This
claim echoes the idea that treating a disease with external medication used to treat
the symptoms would only drive it deeper into the body and conflicts with scientific
studies, which indicate that penicillin treatment produces a complete cure of syphilis
in more than 90% of cases.

A 2006 review by W. Steven Pray of the College of Pharmacy at Southwestern Oklahoma
State University recommends that pharmacy colleges include a required course in
unproven medications and therapies, that ethical dilemmas inherent in recommending
products lacking proven safety and efficacy data be discussed, and that students
should be taught where unproven systems such as homeopathy depart from evidence-based
medicine.

Edzard Ernst, the first Professor of Complementary Medicine in the United Kingdom
and a former homeopathic practitioner, has expressed his concerns about pharmacists
who violate their ethical code by failing to provide customers with "necessary and
relevant information" about the true nature of the homeopathic products they advertise
and sell: "My plea is simply for honesty. Let people buy what they want, but tell
them the truth about what they are buying. These treatments are biologically implausible
and the clinical tests have shown they don't do anything at all in human beings.
The argument that this information is not relevant or important for customers is
quite simply ridiculous."

Michael Baum, Professor Emeritus of Surgery and visiting Professor of Medical Humanities
at University College London (UCL), has described homoeopathy as a “cruel deception”.

In an article entitled "Should We Maintain an Open Mind about Homeopathy?"[186]
published in the American Journal of Medicine, Michael Baum and Edzard Ernst—writing
to other physicians—wrote that "Homeopathy is among the worst examples of faith-based
medicine... These axioms [of homeopathy] are not only out of line with scientific
facts but also directly opposed to them. If homeopathy is correct, much of physics,
chemistry, and pharmacology must be incorrect…".

Regulation and prevalence

Homeopathy is fairly common in some countries while being uncommon in others; is
highly regulated in some countries and mostly unregulated in others. It is practised
worldwide and professional qualifications and licences are needed in most countries.
Regulations vary in Europe depending on the country. In some countries, there are
no specific legal regulations concerning the use of homeopathy, while in others,
licences or degrees in conventional medicine from accredited universities are required.
In Germany, no specific regulations exist, while France, Austria and Denmark mandate
licences to diagnose any illness or dispense of any product whose purpose is to
treat any illness. Some homeopathic treatment is covered by the public health service
of several European countries, including France, the United Kingdom, Denmark, and
Luxembourg. In other countries, such as Belgium, homeopathy is not covered. In Austria,
the public health service requires scientific proof of effectiveness in order to
reimburse medical treatments and homeopathy is listed as not reimbursable[187] but
exceptions can be made;[188] private health insurance policies sometimes include
homeopathic treatment.[34] The Swiss government, after a 5-year trial, withdrew
homeopathy and four other complementary treatments in 2005, stating that they did
not meet efficacy and cost-effectiveness criteria,[189] but following a referendum
in 2009 the five therapies are to be reinstated for a further 6-year trial period
from 2012.[190] The Indian government recognises homeopathy as one of its national
systems of medicine, and a minimum of a recognised diploma in homeopathy and registration
on a state register or the Central Register of Homoeopathy is required to practice
homeopathy in India.

In the United Kingdom, MPs inquired into homeopathy to assess the Government's policy
on the issue, including funding of homeopathy under the National Health Service
and government policy for licensing homeopathic products. The decision by the House
of Commons Science and Technology Committee follows a written explanation from the
Government in which it told the select committee that the licensing regime was not
formulated on the basis of scientific evidence. "The three elements of the licensing
regime (for homeopathic products) probably lie outside the scope of the ... select
committee inquiry, because government consideration of scientific evidence was not
the basis for their establishment," the Committee said. The inquiry sought written
evidence and submissions from concerned parties.

In February 2010 the House of Commons Science and Technology Committee
concluded that:

... the NHS should cease funding homeopathy. It also concludes that the Medicines
and Healthcare products Regulatory Agency (MHRA) should not allow homeopathic product
labels to make medical claims without evidence of efficacy. As they are not medicines,
homeopathic products should no longer be licensed by the MHRA.

The Committee concurred with the Government that the evidence base shows that homeopathy
is not efficacious (that is, it does not work beyond the placebo effect) and that
explanations for why homeopathy would work are scientifically implausible.

The Committee concluded - given that the existing scientific literature showed no
good evidence of efficacy - that further clinical trials of homeopathy could not
be justified.

In the Committee’s view, homeopathy is a placebo treatment and the Government should
have a policy on prescribing placebos. The Government is reluctant to address the
appropriateness and ethics of prescribing placebos to patients, which usually relies
on some degree of patient deception. Prescribing of placebos is not consistent with
informed patient choice - which the Government claims is very important - as it
means patients do not have all the information needed to make choice meaningful.

Beyond ethical issues and the integrity of the doctor-patient relationship, prescribing
pure placebos is bad medicine. Their effect is unreliable and unpredictable and
cannot form the sole basis of any treatment on the NHS.

The Committee also stated:

We conclude that placebos should not be routinely prescribed on the NHS. The funding
of homeopathic hospitals — hospitals that specialise in the administration of placebos
— should not continue, and NHS doctors should not refer patients to homeopaths.

In July 2010 the newly appointed UK Secretary of State for Health deferred to local
NHS on funding homeopathy. A nineteen page document details the Government´s response,
and it states that "our continued position on the use of homeopathy within the NHS
is that the local NHS and clinicians, rather than Whitehall, are best placed to
make decisions on what treatment is appropriate for their patients - including complementary
or alternative treatments such as homeopathy - and provide accordingly for those
treatments." The response also stated that "the overriding reason for NHS provision
is that homeopathy is available to provide patient choice". by February 2011 only
one third of PCTs still funded homeopathy.

History

Historical context

An early assertion that like cures like was made by Hippocrates about 400 BC, when
he prescribed mandrake root, which produced mania, to treat mania, by prescribing
a dose smaller than what would produce mania. In the 16th century the pioneer of
pharmacology Paracelsus declared that small doses of “what makes a man ill also
cures him", anticipating homeopathy, but it was Hahnemann who gave it a name and
laid out its principles in the late 18th century. At that time, mainstream medicine
employed such measures as bloodletting and purging, used laxatives and enemas, and
administered complex mixtures, such as Venice treacle, which was made from 64 substances
including opium, myrrh, and viper's flesh. Such measures often worsened symptoms
and sometimes proved fatal. While the virtues of these treatments had been extolled
for centuries, Hahnemann rejected such methods as irrational and inadvisable. Instead,
he favored the use of single drugs at lower doses and promoted an immaterial, vitalistic
view of how living organisms function, believing that diseases have spiritual, as
well as physical causes.(At the time, vitalism was part of mainstream science; it
wasn't completely discarded until the 20th century, with the development of microbiology,
the germ theory of disease, and advances in chemistry.) Hahnemann also advocated
various lifestyle improvements to his patients, including exercise, diet, and cleanliness.

Hahnemann's concept

Hahnemann conceived of homeopathy while translating a medical treatise by Scottish
physician and chemist William Cullen into German. Being skeptical of Cullen's theory
concerning cinchona's action in intermittent fever, Hahnemann ingested some of the
bark specifically to see if it cured fever "by virtue of its effect of strengthening
the stomach". Upon ingesting the bark, he noticed few stomach symptoms, but did
experience fever, shivering and joint pain, symptoms similar to some of the early
symptoms of intermittent fever, the disease that the bark was ordinarily used to
treat. From this, Hahnemann came to believe that all effective drugs produce symptoms
in healthy individuals similar to those of the diseases that they treat. This later
became known as the "law of similars", the most important concept of homeopathy.
The term "homeopathy" was coined by Hahnemann and first appeared in print in 1807,
although he began outlining his theories of "medical similars" or the "doctrine
of specifics" in a series of articles and monographs in 1796.

Hahnemann began to test what effects substances produced in humans, a procedure
that would later become known as "homeopathic proving".These time-consuming tests
required subjects to clearly record all of their symptoms as well as the ancillary
conditions under which they appeared. Hahnemann saw these data as a way of identifying
substances suitable for the treatment of particular diseases. The first collection
of provings was published in 1805 and a second collection of 65 remedies appeared
in his book, Materia Medica Pura, in 1810.[216] Hahnemann believed that large doses
of drugs that caused similar symptoms would only aggravate illness, so he advocated
extreme dilutions of the substances; he devised a technique for making dilutions
that he believed would preserve a substance's therapeutic properties while removing
its harmful effects,proposing that this process aroused and enhanced "the spirit-like
medicinal powers of the crude substances". He gathered and published a complete
overview of his new medical system in his 1810 book, The Organon of the Healing
Art, whose 6th edition, published in 1921, is still used by homeopaths today.

19th century: rise to popularity and early criticism

Homeopathy achieved its greatest popularity in the 19th century. Dr. John Franklin
Gray (1804–1882) was the first practitioner of Homeopathy in the United States,
beginning in 1828 in New York City. The first homeopathic schools opened in 1830,
and throughout the 19th century dozens of homeopathic institutions appeared in Europe
and the United States. By 1900, there were 22 homeopathic colleges and 15,000 practitioners
in the United States. Because medical practice of the time relied on ineffective
and often dangerous treatments, patients of homeopaths often had better outcomes
than those of the doctors of the time. Homeopathic remedies, even if ineffective,
would almost surely cause no harm, making the users of homeopathic remedies less
likely to be killed by the treatment that was supposed to be helping them. The relative
success of homeopathy in the 19th century may have led to the abandonment of the
ineffective and harmful treatments of bloodletting and purging and to have begun
the move towards more effective, science based medicine.[203] One reason for the
growing popularity of homeopathy was its apparent success in treating people suffering
from infectious disease epidemics.During 19th century epidemics of diseases such
as cholera, death rates in homeopathic hospitals were often lower than in conventional
hospitals, where the treatments used at the time were often harmful and did little
or nothing to combat the diseases.

From its inception, however, homeopathy was criticized by mainstream science. Sir
John Forbes, physician to Queen Victoria, said in 1843 that the extremely small
doses of homeopathy were regularly derided as useless, "an outrage to human reason".
James Young Simpson said in 1853 of the highly diluted drugs: "No poison, however
strong or powerful, the billionth or decillionth of which would in the least degree
affect a man or harm a fly." 19th century American physician and author Oliver Wendell
Holmes, Sr. was also a vocal critic of homeopathy and published an essay in 1842
entitled Homœopathy, and its kindred delusions. The members of the French Homeopathic
Society observed in 1867 that some of the leading homeopathists of Europe not only
were abandoning the practice of administering infinitesimal doses but were also
no longer defending it.] The last school in the U.S. exclusively teaching homeopathy
closed in 1920.